Polyurethane Elastomers Research Articles

‘Rigid–flexible’ strategy for high-strength, near-room-temperature self-healing, photo-thermally functionalised lignin-reinforced polyurethane elastomers

Lignin is the most abundant and only renewable aromatic polymer in nature. Herein, a flexible matrix and the rigid lignin were rationally integrated to prepare high-strength, near-room-temperature self-healing, processable lignin-reinforced polyurethane elastomers (LZPUs). Reversible hydrogen and oxime–amino ester bonds were introduced into the matrix to provide excellent dynamic properties and abundant ligands for lignin–matrix coordination bonds. Abundant metal coordination bonds were constructed between the matrix and lignin via the introduction of Zn2+, which not only effectively enhances the dispersibility and compatibility, but also provides an excellent energy dissipation mechanism for the LZPUs. One of the prepared elastomers, LZPUs, exhibited a high strength of 40.5 MPa, which is twice that of the blank sample and 1.6 times that of the sample without Zn2+. It maintained kinetic stability at mild temperature, but it exhibited a self-healing efficiency of 91.3 % in strength and 99.8 % in elongation at break after decoupling with trace ethanol (≈ 50 μL) at 35 °C. It exhibited a self-healing efficiency of 93.6 % in strength under 1 sun irradiation (0.1 W cm−2) for 4 h. We believe this elastomer offering high mechanical properties with multi-functionality can be applied in flexible drives and photo-thermal power generation.

Lignin-carbohydrate complex-based polyurethane elastomer with outstanding mechanical strength, photothermal efficiency, and enhanced recyclability

Addressing plastic pollution and reducing reliance on petroleum reserves necessitates the development of bio-based materials from renewable resources. Lignin-carbohydrate complexes (LCC) extracted from lignocellulose, abundant in aromatic rings and hydroxyl groups, offer a promising alternative to conventional polyols in polyurethane synthesis. Historically, the limited solubility of LCC in polyols has posed significant challenges in fabricating high-performance biomass-based polyurethanes. This study presents an innovative LCC-based polyurethane elastomer, synthesized from LCC, polyols, and isocyanate building blocks. By replacing traditional polyols with hydroxyl-rich LCC, the resulting polyurethane elastomer (PUC) exhibits exceptional mechanical properties and photothermal conversion efficiency. The material boasts a maximum tensile strength of 20.94 MPa, a fracture strain of 1167.39 %, an elastic recovery rate of 91.4 %, and a peak photothermal conversion temperature of 125 °C. These outstanding attributes are ascribed to a robust network of dynamic covalent and hydrogen bonds. Moreover, the incorporation of LCC notably enhances the recyclability of the polyurethane elastomer and provides effective UV-blocking properties. This research not only broadens the spectrum of raw materials available for polyurethane production but also introduces innovative methodologies for the practical utilization of LCC, representing a notable advancement in sustainable materials science.

A Camel-Fur-Inspired Micro-Extrusion Foaming Porous Elastic Fiber for All-Weather Dual-Mode Human Thermal Regulation.

Maintaining the stability of human body temperature is the basis of ensuring the normal life activities of witness, and the emergence of various functional clothing is committed to assisting the human body temperature in thermal comfort range in the changeable environment. However, achieve dual-mode thermal regulation for cooling and insulation on an integrated material without energy input and addition of functional particles has thus far been a huge challenge. Herein, a biomimetic camel-fur designed micro-extruded physically foamed porous elastic fiber (MEPF) using thermoplastic polyurethane (TPU) elastomer as raw material is reported, and its dual-layered fabric (MEPFT-d) for effective personal thermal comfortable management at extreme temperature differences. Benefit from its micro-nano-pores structure, MEPFT-d represents radiate cooling capacity by high solar reflectance and emissivity, behaves low thermal conductivity delaying heat scattering, and promotes evaporative cooling by unidirectional water transport. These excellent properties ensure that MEPFT-d reduces heat loss in cold weather (7.2 °C higher than cotton) and blocks outside heat in hot weather (10.2 °C lower than cotton), which is suitable for various complex outdoor scenes. The cost-effectiveness and superior wearing comfort of this work provide innovative pathways for sustainable energy, smart textiles, and personal thermal comfort applications.

Microstructured CNTs/Cellulose Aerogel for a Highly Sensitive Pressure Sensor.

Flexible sensors have been applied in human health monitoring and biomedical research, but producing high-performance piezoresistive sensors at low cost is still challenging. To address these shortcomings, we proposed a microstructured carbon nanotube (CNT)/cellulose aerogel-based pressure sensor. The sensor consists of three parts, i.e., cellulose/poly(vinyl alcohol)/CNT aerogel-based sensing layer and top and bottom thermoplastic polyurethane elastomer (TPU)/silver nanowire (Ag NW) nanofiber electrode. The aerogel is fabricated using a simple freeze-drying method and an easy electrospinning method to obtain the nanofiber-based electrode. Two TPU/Ag NW nanofiber electrodes sandwiched the aerogel with a microstructure in the middle. Benefiting from the microcone and micropore structures on the nanofiber electrode, the assembled sensors show a high sensitivity of 66.4 kPa-1, a significant detection boundary of 50 kPa, and an excellent response speed of 10 ms. The high sensing performance enables the sensor to monitor physiological signals, Morse code interactions, and gesture recognition. With the help of machine learning, the success rate of gesture recognition is as high as 98.8%. The preparation of this pressure sensor based on an aerogel shows excellent health and environmental monitoring potential as an artificial skin.

A robust bio-based polyurethane employed as surgical suture with help to promote skin wound healing

Designing bio-based polyurethane materials with excellent mechanical, biocompatibility, and self-healing properties simultaneously is currently a significant challenge due to the increasing demands for high-performance materials. In this study, we propose an asymmetric backbone strategy utilizing bio-based polycarbonate as the soft segment, equimolar ratios of lysine diisocyanate and isophorone diisocyanate as asymmetric hard segments, and isophorone diamine as the chain extender. The resulting polyurethane elastomers exhibit excellent mechanical properties, including high tensile stress (46.1 MPa), toughness (213.9 MJ/m3), and fracture energy (98.47 kJ/m3). The polyurethane elastomers demonstrate good self-healing and recyclable properties under simple heat treatment. Furthermore, biological experiments confirm the degradability and bio-safety of the bio-based polyurethane elastomers, which have shown potential in accelerating wound healing in mice when used as surgical sutures. These findings highlight the promising prospects of the obtained polyurethane elastomers in various applications, including biomedicine, flexible sensing, and electronic components.

Semaglutide functional electrospinning nanofiber membrane rescues apoptosis and promotes diabetic wound healing

The healing of diabetic wounds is a difficult problem due to decreased proliferation, and migration of epidermal and endothelial cells. Here we reported semaglutide-loaded nanofiber membrane to promote diabetic wound healing through suppressing reactive oxygen species production and accelerating angiogenesis in a diabetic rat model. The fiber membrane was prepared by an electrostatic spinning technique. The fiber membrane consisted of thermalplastic polyurethane elastomer, polyvinyl butyral ester, zein and semaglutide (SMGT). The fiber membrane had a uniformly distributed diameter, suitable water vapor transmission rate, good water absorption and retention properties. In vivo data determined that the SMGT-loaded nanofiber membrane was able to promote normal skin pathological structure formation in regenerated tissue. In vitro experiments displayed that SMGT might facilitate HG-induced endothelial cell dysfunction by inhibiting ROS production. The present study provided a theoretical basis for the extensive application of SMGT in the treatment of diabetic ulcers and other wounds.

Room-temperature self-healing polyurethane with superior mechanical properties based on supramolecular structure for flame retardant application

Self-healing polymers, with their ability to extend service life and conserve resources, have garnered significant attention across various fields due to their immense potential applications. However, most repairable polymers typically require high temperatures for repair, and their relatively weak mechanical properties limit their practical use. Moreover, the flammability of polymers not only poses safety hazards during use but also fails to meet specific requirements for flame retardancy in certain fields. Addressing these issues, this study successfully designed a reactive self-extinguishing room-temperature self-healing polyurethane (PU) by introducing hyperbranched catechol (DBPA) onto the PU main chain. The prepared self-healing PU elastomer (DPU) exhibited high tensile strength (∼51.2 MPa), outstanding toughness (∼119.0 MJ/m3), recyclability, and good flame retardancy. Through intermolecular and intramolecular multilevel hydrogen bonding, the prepared DPU0.6 achieved room-temperature self-healing with an efficiency of approximately 71.2 %. The results showed that the addition of trace amounts of DBPA (0.6 wt%) significantly enhanced the flame retardancy and thermal stability of DPU. Compared to DPU0, the heat release rate (HRR) of DPU0.6 decreased by approximately 13 %, the total heat release (THR) reduced by 18 %, and the time to ignition (TTI) was extended by 7 s (reduced by ∼ 21 %). This study not only provides insights into the synthesis and design of novel self-healing PU but also further expands the application scope of self-healing PU.

Multiphase hydrogen bonding strategies room temperature self-healing, recyclable polyurethane elastomers for applications in flame retardant materials

Novel elastomers offer new opportunities to develop multifunctional materials in terms of combining mechanical strength, room-temperature self-healing properties and recyclability. However, self-healing polymers have high mechanical strength at high internal cross-linking density, but restrict the movement of molecular chain segments leading to reduced self-healing efficiency. The presence of microphase-separated structures makes the polymers poorly efficient for repair at room temperature. In this paper, a multiphase hydrogen bonding (H-bonding) strategy is used to introduce an aliphatic ring into the system to form a repeating unit with the hard segments, as well as a bis-benzene ring structure with a methylene linkage to disrupt the crystallization of the hard domains. Specifically, PUPI-M2I3 has a mechanical tensile strength of 17.93 MPa, an excellent tensile ratio of 1109.88 %, the sample can recover 95.93 % at room temperature after 24 h of fracture and stretching, with excellent room temperature self-healing performance and recyclability. Meanwhile, the self-healing flame-retardant material based on PUPI-M2I3 is developed by comprehensive consideration, which opens a new way for the research and development of flame-retardant materials.

Clinical breakage, slippage and acceptability of two commercial ultra-thin polyurethane male condoms compared to a commercial thin latex condom: a randomised, masked, 3 way crossover, multi centre controlled study (SAGCS 2)

BackgroundAlthough natural rubber latex remains dominant as the primary manufacturing material for male condoms synthetic materials first introduced in the early 1990s address many of the limitations of latex including the risk of allergies. Polyurethane elastomers allow condoms to be made significantly thinner to provide greater sensitivity and encourage greater use of condoms for contraception and STI prophylaxis.The primary objective of this Study was to evaluate the breakage, slippage and acceptability of two ultra-thin polyurethane condoms against a thin control latex male condom, designated latex C, in a randomized, cross over, masked, non-inferiority study. The condom designated Polyurethane A was designed for markets where 52/53 mm wide latex condoms are preferred whereas the condom designated Polyurethane B was designed for markets where the smaller 49 mm wide latex condom is preferred.MethodsThe Study was designed to meet the requirements specified in ISO 29943–1: 2017 and FDA guidelines for clinical studies on synthetic condoms. It was conducted by two Essential Access Health centres, one in Northern California and the other in Southern California. Sexually active heterosexual couples (300) aged between 18 and 45 years were recruited to use three sets of five condoms in a block randomized order, recording breakage, slippage and acceptability after each use. A total of 252 couples contributed 2405 evaluable condom uses per protocol for the Condom A versus Latex C comparison (1193 Polyurethane A plus 1212 Latex C), and 247 couples provided 2335 evaluable condom uses per protocol for the Condom B versus Latex C comparison (1142 Polyurethane B plus 1193 Latex C). Only condoms used for vaginal intercourse were included in the analysis.FindingsAlthough the total failure rates (breakage and slippage) for the polyurethane condoms were higher than for the control Latex C condom, all condoms performed extremely well with low failure rates compared to similar condom studies. Condom Polyurethane A met the noninferiority requirements specified in ISO 23409:2011 relative to Latex C, the control NR latex condom, in the full Study population. While condom Polyurethane B did not meet the noninferiority requirement for the full Study population, it did meet the noninferiority requirement when analysis was restricted to the intended population (men with penis lengths ≤ 170 mm).Trial registration The Study is registered with ClinicalTrials.gov, NCT04622306, Protocol Reference SAGCS 2, initial release date 11/02/2020.

MDI-PTMG-based TPU modified asphalt: Preparation, rheological properties and molecular dynamics simulation

Thermoplastic polyurethane elastomer (TPU) modified asphalt was prepared by a two-step process using MDI and PTMG. The improvement effects of different TPU content on high-and low-temperature rheological properties and thermal stability of asphalt were studied through experimental tests. The results showed that TPU could enhance the high-temperature properties of asphalt obviously. The improvement effect was more significant with the increase of TPU content. At the same time, glass transition temperature (Tg) of asphalt decreased with the increase of TPU content, indicating that TPU could improve the low-temperature performance of asphalt. These experimental results were further verified by the Molecular dynamics (MD) simulation results. Materials Studio 8.0 was used to establish the molecular models of asphalt, TPU and TPU modified asphalt. The effects of TPU content on mechanical modulus and Tg of asphalt were studied by MD simulation. The results revealed that TPU formed a close structure with asphalt to improve the structural stability of asphalt. And the free volume fraction of the modified asphalt decreased with the increase of TPU content. Thus, the high-temperature properties of asphalt were improved. The calculated Tg and moduli obtained from MD simulation accorded well with the experimental results from DSC and DSR, respectively. This study suggests a novel way to provide guidance for the development of TPU modified asphalt.

Hybrid toughening effect of flax fiber and thermoplastic polyurethane elastomer in 3D‐printed polylactic acid composites

AbstractFlax fiber has emerged as a promising, eco‐friendly alternative to traditional synthetic reinforcement in polymer composites. However, manufacturing biocomposites using three‐dimensional (3D) printing technology is typically accompanied by significant processing challenges and weak product performance under dynamic loading conditions. This study aims to unlock the potential of 3D‐printed polylactic acid (PLA) by incorporating chemically modified chopped flax fibers and thermoplastic polyurethane elastomer to improve impact strength and processability. To achieve this, we employed the fused deposition modeling (FDM) technique to prepare composite specimens for the study. The crystallization behavior, tensile and impact properties, as well as the fracture behavior of the composites were investigated. The findings suggest that our approach stands out because it not only facilitates the challenging task of 3D printing PLA with fiber additives of high weight fraction and high aspect ratio but also results in a remarkable 120% enhancement in impact strength and an around 31.2% increase in tensile elongation compared to neat PLA, without compromising the elastic modulus.Highlights Flax fibers were modified through alkalization and silanization. Alkalization significantly enhanced printing quality. Silanization reduced fiber attrition and doubled the fiber aspect ratio. TPU particles facilitated the 3D printing of biocomposites. For the first time, the hybrid strategy doubled the impact strength of PLA.

Tough, high-strength, flame-retardant and recyclable polyurethane elastomers based on dynamic borate acid esters

With the wide application of polyurethane elastomers, it is necessary to develop recyclable, fire-retardant polyurethane elastomers with great mechanical properties to comply with industrial requirements. Herein, we fabricated a flame-retardant, recyclable, strong yet tough polyurethane elastomer (PIDB-1) based on dynamic borate acid esters. The introduction of phosphaphenanthrene and boron-containing groups endow PIDB-1 with great flame retardancy, as reflected by it achieving the vertical burning (UL-94) V-0 rating. The PIDB-1 film shows high visible light transmittance, and its transmittance reaches 90 % at the wavelength of 800 to 900 nm. The tensile strength of PIDB-1 is 54.9 MPa, and its toughness reaches 207.8 kJ/m3, indicative of superior mechanical properties. Meanwhile, the dynamic borate acid esters allow the PIDB-1 elastomer to possess physical and chemical recyclability. When using PIDB-1 as a polymer matrix for carbon fiber-reinforced polymer composites, the carbon fibers can be fully recycled. This work provides an integrated design strategy for creating transparent, flame-retardant, recyclable polyurethane elastomers combining high strength and toughness based on dynamic borate ester bonds, which is expected to find wide applications in different industries.

Hierarchical H-bonding and metal coordination bonds enabled supramolecular dual networks for high-performance energy-dissipation

Natural organisms have superior material properties such as mechanical adaptability, impact protection, and self-healing to protect the body from complicated external environments, fascinating the development of functional supramolecular elastic materials with biomimetic protective features. Herein, a dual physically crosslinked supramolecular polyurethane (PU) network with strain-hardening effect is synthesized by incorporating hierarchical hydrogen bonds (H-bond) and metal coordination bonds into an elastomer matrix. A moderate content of quadruple H-bonds is critical for achieving a prominent toughness and a considerable strain-at-break owing to the strain hardening effect enabled by the hierarchical H-bonds. When the Zn-to-pyridine coordination bonds were introduced to the supramolecular PU, the strength, toughness, and energy dissipation properties were further enhanced attributing to the dual physical crosslinking networks. The dynamic dissociation and association of the sacrificial H-bonds and Zn-to-pyridine coordination bonds induced significant strain hardening effect and enabled tremendous energy absorption and self-healing properties. Besides, the supramolecular PU elastomers and their blends were foamed via scCO2 foaming to produce supramolecular foams containing dynamic bonds. The composite foam could effectively reduce the impact force from 6085 N to 373 N and achieve an outstanding energy absorption efficiency of 93.87% owing to the synergistic effect of porous structure and dual physically crosslinked networks. This work provides an innovative strategy for designing high-performance energy absorbing supramolecular elastomers and cushioning foams with reversible bonds.

Compressive behavior and visco-hyperelastic constitutive of polyurethane elastomer over a wide range of strain rates

Polyurethane elastomers (PUEs) will experience different strain rates in different application scenarios. Therefore, it is of great significance to study the mechanical properties of PUE under a wide range of strain rates and establish a constitutive model that considers strain rates with high accuracy and few parameters. In this study, the quasi-static and dynamic compression tests of two types of PUEs (PUE55 and PUE85) were carried out, and investigated the strain rate effect of the materials. Based on the Mooney-Rivlin hyperelastic model and the Prony series, a compressible visco-hyperelastic constitutive model for PUE was established. Different from the conventional constant relaxation time in Prony series, two relaxation times that vary exponentially with principal stretch were proposed based on the relaxation test to describe the strain rate effect of the material at low and high strain rate respectively. In addition, using the visco-hyperelastic constitutive model to obtain the model inputs of the Simplified rubber/foam model in LS-DYNA, the impact process of the Metal/PUE composite projectile was reproduced under different impact conditions through the finite element simulation. Simulation results verified the visco-hyperelastic model in generating numerical model material parameters and the rationality of the Simplified rubber/foam model in describing PUEs.

Novel Design of Eco-Friendly High-Performance Thermoplastic Elastomer Based on Polyurethane and Ground Tire Rubber toward Upcycling of Waste Tires.

Waste rubber tires are an area of global concern in relation to reducing the consumption of petrochemical products and environmental pollution. Herein, eco-friendly high-performance thermoplastic polyurethane (PU) elastomers were successfully in-situ synthesized through the incorporation of ground tire rubber (GTR). The excellent wet-skid resistance of PU/GTR elastomer was achieved by using mixed polycaprolactone polyols with Mn = 1000 g/mol (PCL-1K) and PCL-2K as soft segments. More importantly, an efficient solution to balance the contradiction between dynamic heat build-up and wet-skid resistance in PU/GTR elastomers was that low heat build-up was realized through the limited friction between PU molecular chains, which was achieved with the help of the network structure formed from GTR particles uniformly distributed in the PU matrix. Impressively, the tanδ at 60 °C and the DIN abrasion volume (Δrel) of the optimal PU/GTR elastomer with 59.5% of PCL-1K and 5.0% of GTR were 0.03 and 38.5 mm3, respectively, which are significantly lower than the 0.12 and 158.32 mm3 for pure PU elastomer, indicating that the PU/GTR elastomer possesses extremely low rolling resistance and excellent wear resistance. Meanwhile, the tanδ at 0 °C of the above-mentioned PU/GTR elastomer was 0.92, which is higher than the 0.80 of pure PU elastomer, evidencing the high wet-skid resistance. To some extent, the as-prepared PU/GTR elastomer has effectively solved the "magic triangle" problem in the tire industry. Moreover, this novel research will be expected to make contributions in the upcycling of waste tires.

An experimental and numerical investigation of ballistic penetration behaviors of deployable composite shells

Bistable composite shells are suitable candidates for deployable space structures due to high stiffness to weight ratio as well as large volume reduction. Nevertheless, impact performance of bistable composite shells conflicting with space debris have been rarely studied. In this paper deployable hybrid composites constructed with combinations of carbon–carbon, carbon–kevlar, kevlar–kevlar, high-energy-absorption graphene-reinforced polyurethane elastomers are developed, and their ballistic penetration behaviors are experimentally and computationally studied. The influences of ballistic velocity on the absorbed energy, the residual velocity and damage morphology of the targets are investigated in both deployed and coiled stable states. The results show that severe local damages were observed for the carbon–carbon and carbon–kevlar samples after penetration with various velocities even first cosmic velocity, and the sample of deployable hybrid composite shell yielded the best ballistic impact resistance. The total energy absorption performance of the hybrid composite structure was greatly improved by introducing graphene-reinforced polyurethane elastomers without losing the deployability. Additionally, investigation on the energy absorption capability of deployed laminated shells with various curvature radii indicated that the curvature radius had a significant effect on the anti-penetration performance.

Controllable Design and Synthesis of Polyurethane Elastomers Containing Polar Dangling Chains with High Mechanical Properties and Wide Damping Temperature Range.

Vibration and noise severely affect the operation of mechanical equipment and is also detrimental to human health. Therefore, the development of high performance damping materials is crucial. However, current methods to improve damping properties often come at the expense of mechanical properties, resulting in inferior mechanical performance of materials. In order to address the issue of imbalance between damping properties and mechanical properties in polyurethane damping elastomers. In this study, polyester dangling chains containing polar groups are synthesized and introduced into polyurethane. The obtained polyurethane exhibited an effective damping temperature range of 154 °C (-54 °C to 100 °C) and a tensile strength of 15.82 MPa. Furthermore, dynamic mechanical analysis and broadband dielectric relaxation spectroscopy are combined to investigate the influence of polar dangling chains on the structure and properties of polyurethane. The degree of microphase separation increases after the introduction of polar dangling chains, indicating enhances intermolecular interaction forces, facilitating the formation of hydrogen bond between the main chain and dangling chains, thereby increasing molecular chain friction and energy dissipation. This work overcomes the challenge of balancing the damping and mechanical properties of polyurethane, providing a new strategy for designing high performance polyurethane damping elastomers.

A Novel Biomedical Polyurethane Material With Optimized Optical and Mechanical Properties Is Developed

Abstract This research aims to design and develop a novel polyurethane elastomer (PUE) material with potential for biomedical optical applications. The study investigates the influence of hard segment (HS) content on transparency and tensile strength to optimize optical and mechanical properties. A one-step polymerization method is employed to synthesize a series of PUEs based on polyester, poly (3-methyl-1,5-pentandioladipate) (PMPA), diisocyanate (4,4-methylene bis (phenyl isocyanate) (MDI)), and the chain extender 1,4 butanediol (BD). By varying the ratios of PMPA/BD/MDI, PUE samples with different HS concentrations are synthesized. Analytical techniques including infrared spectroscopy, refractometer, UV/visible spectrophotometer, and tensile tests confirm the chemical structure of the synthesized PMPAPUE materials and investigate refractive indices (n), transmission spectra, and Young's modulus (YM), respectively. Films (PUE-1, PUE-2, and PUE-3) prepared using solvent-casting techniques exhibit varying optical and mechanical properties. PUE-1, with low HS content, demonstrates excellent transparency, with n = 1.59 and 89.63% of total transmitted light, and possesses excellent elastic properties with a YM of 10.654 MPa and a high strain value of S = 303.7%, meeting lens material requirements, promising for biomedical optical applications. Conversely, PUE-2 and PUE-3, with high HS content, are translucent and stiffer materials exhibiting higher YM, suitable for polymer processing, and tissue engineering applications. The optimization of the material's properties was achieved by carefully tailoring the composition of HS and soft segments, raw material ratios, and optimizing reaction conditions.

Synergistic integration of dynamic acylsemicarbazide bonds and disulfide bonds into polyurethane: A facile strategy to surmount the tradeoff between mechanical strength and self‐healing capacity of elastomers

AbstractThe polymeric materials can simultaneously possess high mechanical properties and outstanding self‐healing performance under mild condition have found widespread applications in various fields. However, this type of polymers is exceedingly rare due to the trade‐off between mechanical robustness and chain flexibility for healing. In this study, we designed a facile strategy for synergistic integration of dynamic acylsemicarbazide (ASC) bonds and disulfide bonds into polyurethane elastomer by the reaction between 3,3′‐dithiobis(propionohydrazide) and isocyanate‐terminated Pre‐PU. The obtained elastomer ASC‐SS‐PU not only possesses an outstanding tensile strength (17.1 MPa), good stretchability (735%) and high toughness (57.16 MJ·m−3), but also exhibits excellent self‐healing performance under mild condition. The healing efficiency of the damaged ASC‐SS‐PU samples (breakage rate >90%) can reach over 70% healing at 60°C for 40 min, which is much lower than conventional ASC‐based PU elastomer. Considering the simple and easy‐to‐scaleup preparation process and commercially available low‐cost raw materials, outstanding mechanical strength and toughness, as well as high healing efficiency under mild condition, the ASC‐SS‐PU elastomer as self‐healing but strong materials have great potential for use in various fields.

Ultratough Supramolecular Polyurethane Featuring an Interwoven Network with Recyclability, Ideal Self-Healing and Editable Shape Memory Properties.

Developing multifunctional polymers with excellent mechanical properties, outstanding shape memory characteristics, and good self-healing properties is a formidable challenge. Inspired by the woven cross-linking strategy, a series of supramolecular polyurethane (PU) with an interwoven network structure composed of covalent and supramolecular cross-linking nodes have been successfully synthesized by introducing the ureido-pyrimidinone (UPy) motifs into the PU skeleton. The best-performing sample exhibited ultrahigh strength (∼77.2 MPa) and toughness (∼312.7 MJ m-3), along with an ideal self-healing efficiency (up to 90.8% for 6 h) and satisfactory temperature-responsive shape memory effect (shape recovery rates up to 96.9%). Furthermore, it ensured recyclability. These favorable properties are mainly ascribed to the effective dissipation of strain energy due to the disassembly and reconfiguration of supramolecular nodes (i.e., quadruple hydrogen bonds (H-bonds) between UPy units), as well as the covalent cross-linking nodes that maintain the integrity of the polymer network structure. Thus, our work provides a universal strategy that breaks through the traditional contradictions and paves the way for the commercialization of high-performance multifunctional PU elastomers.